PBG material antennas have the advantage of exhibiting a reduced footprint with respect to other types of antennas, such as reflector-type, lens-type or horn-type antennas.
Such PBG material antennas are described in particular in patent application FR 99 14521, published under No. 2 801 428 in the name of C.N.R.S. (Centre National de la Recherche Scientifique). This patent describes precisely an embodiment of a PBG material exhibiting a single defect forming a leaky resonant cavity. Moreover, and although no embodiment of this variant is described explicitly, this patent also envisages the possibility of creating multiband antennas from PBG materials. Specifically, this patent teaches that a defect created in the PBG material makes it possible to produce a narrow passband within a wider stopband of this PBG material. Consequently, to create multiband antennas, several defects must be created in the PBG material so as to create several narrow passbands within the same stopband of the PBG material. This is what is indicated on page 10, lines 23 to 25 of this patent application FR 99 14521.
It is recalled here that a multiband antenna refers to an antenna suitable for working at several different, mutually distinct working frequencies. Moreover, the multiband antenna exhibits, for each of the working frequencies, the same radiation pattern and the same radiation polarization.
The construction of multiband antennas according to the teaching of patent application FR 99 14521 has turned out to be complicated, on account in particular of the difficulties of design of a multidefect PBG material.
The invention aims to remedy this drawback by proposing a frequency multiband antenna made of a PBG material which is simpler to construct.